This invention pertains to a method and an apparatus for the regeneration of asynchronous data signals of a given character structure which arrive on a transmission line time distorted and at a signalling rate which deviates from the nominal signalling rate and after detection are fed, at a character rate determined by the arriving signals, to a regeneration device which retransmits the data signals at a signalling rate determined by a timing generator included in the regeneration device.
In the Swedish published application No. 7310969-6 a simple regeneration principle is described according to which the asynchronous data signals after detection are retransmitted at the same instantaneous character rate as they are received, i.e. with a constant character delay. The time position of an arriving character is established by means of the opening start element which, due to the rate deviation and time distorsion being present, will be more or less displaced compared to its nominal time position. If the start element and the subsequent data elements are retransmitted with equal lengths the finishing stop element will be of a varying length in correspondence with the above mentioned time position displacements. When transmitting over long distances the data signals may have to pass several regenerators and there is a risk, then, that the stop elements may be exposed to such a great distorsion that the following start elements cannot be detected and data loss arises. In order to avoid that, it is necessary during the regeneration also to observe the stop element so that its length will be as constant as possible and, consequently, the regenerated character length be adjusted to the incoming average character rate. This is achieved, according to the invention, in such a way that the retransmission of characters is effected with a varying delay which is adjusted depending on the deviation of the arriving characters from their nominal time positions. The characteristics of the invention appear from the claims.